(function($){
  	$.fn.snow = function(options){
		var $flake = $('<div id="snowbox" />').css({'position': 'absolute','z-index':'1', 'top': '-50px'}).html('❄'),
		documentHeight = $(document).height(),
		documentWidth = $(document).width(),
		defaults = {
			minSize		: 10,
			maxSize		: 20,
			newOn		: 600,
			flakeColor	: "#AFDAEF" /* 此处可以定义雪花颜色，若要白色可以改为#FFFFFF */
		},
		options	= $.extend({}, defaults, options);
		var interval = setInterval(function(){
			var startPositionLeft = Math.random() * documentWidth - 100,
			startOpacity = 0.5 + Math.random(),
			sizeFlake = options.minSize + Math.random() * options.maxSize,
			endPositionTop = documentHeight - 200,
			endPositionLeft = startPositionLeft - 500 + Math.random() * 500,
			durationFall = documentHeight * 10 + Math.random() * 5000;
			$flake.clone().appendTo('body').css({
				left: startPositionLeft,
				opacity: startOpacity,
				'font-size': sizeFlake,
				color: options.flakeColor
			}).animate({
				top: endPositionTop,
				left: endPositionLeft,
				opacity: 0.2
			},durationFall,'linear',function(){
				$(this).remove()
			});
			// 设置存活时间，9秒后删除元素
			setTimeout(function(){
				// 获取要删除的div元素
				var divElement = document.getElementById("snowbox");
				// 删除div元素
				divElement.remove();
			}, 9000);
		}, options.newOn);
    };
})(jQuery);
$(function(){
	$.fn.snow({ 
	minSize: 5, /* 定义雪花最小尺寸 */
	maxSize: 25,/* 定义雪花最大尺寸 */
	newOn: 600  /* 定义密集程度，数字越小越密集 */
	});
});